1. Field of the Invention
The present invention relates generally to an electrical component and a method of manufacturing the same, and, more particularly, to a coil electrical component and a method of manufacturing the same.
2. Description of Prior Art
A coil electrical component is usually designed to resist change of the current. For example, when the current flows through the inductor, a magnetic field is produced. Change of the magnetic field may induce change of the voltage and resist change of the current. The ability to inhibit the current change is called inductance.
In general, the early common inductor is ring inductor 1a having functions of self-shielding, high coupling and premature saturation, as shown in FIG. 1. In recent years, the demand for the inductor mounted on the circuit board is the trend of miniaturization, however, while the ring inductor 1a is larger in volume. Although the ring inductor used in the power supply equipment do not need to consider the volume issue, the manpower and time cost for winding the coil are also relatively increased. Compared to the “1” shaped inductor 1b or the “I” shaped inductor 1c as shown in FIG. 1, the volume of the two inductors are smaller than the ring inductor 1a and the coil 1s 2b and 12c can be formed by mechanical assistance. However, the magnetic field lines of the aforementioned three inductors are exposed to the air and which results to non-uniform in magnetic field lines and low saturation current.
The closed inductor has characteristics of low resistance, high inductance and high-current durability. Conventional technique provides an inductor 2a with a housing as shown in FIG. 2, including a housing 23a and core material 21a surrounding with coils (not shown) of the core material 21a, however, in the case of the tolerances for the size of the housing 23a and the core material 21a are too large, it is difficult to assemble into the inductor 2a. Therefore, conventional technique provides an integrated powder alloy inductor 2b as shown in FIG. 2. The magnetic powder, the coil 22b and magnetic powder are sequentially added in the mold and a high pressure (e.g., 200 kg/cm2) is applied (for example, by stamping with a punch) in order to pressing the magnetic powder into core material 21b and the inductor 2b is formed. However, such technique cannot be used in any shape of mold. Since the finished product in the mold is likely to be broken during the high pressure molding step, equipment providing high pressure and specific shapes of mold withstand high pressure are necessary. In addition, the large scale inductor as an example, it is not easy to reduce the production cost, since an extremely large pressure is needed to provide the mechanism exerting pressure on the inductor for molding. Furthermore, conventional technique also provides an inductor 2c as shown in FIG. 2. Since the inductor 2c includes core material 21c, coil 22c and coating body 23c, in case of adopting the aforementioned high pressure pressing technique for molding the coating body 23c, the core material 21c is inevitably to be broken.
Therefore, currently manufacturing method of the inductor mostly uses a mold placing the core material 21c and the coil 22c, and then the gel with the magnetic powder is injected in the mold. After heating at high temperature, the coating body 23c is molded. However, while using the gel coating the core material and the coil may avoid the problem of broken core material by the aforementioned high pressure pressing, the bubbles may be produced when the gel is injected into the mold. It is difficult to achieve a vacuum state during the process, besides, owing to the specific gravity of the magnetic powder is greater than the gel, thus settlement phenomena may occur in the gel. These problems or phenomena may often affect the characteristics of the inductors.